Pandora, already in a heated battle with, among others, Spotify and Sirius XM ( SIRI), had figured out ways to keep growing its popular service, albeit amid some "fading notes."

Last week, the company announced total listening hours for the month of August rose 16% year over year to 1.35 billion hours. The number of people that sign on to the service each month also increased, by almost 30% to 72.1 million, which represents 1% sequential improvement. What this means is that, with a year-over-year improvement of 116 basis points, Pandora now accounts for 7.5% market share of the U.S. radio listening audience.

This is impressive growth. Admittedly, I haven't been Pandora's biggest supporter. But there is no way to spin this performance without giving the company its due credit. Unfortunately, however, making money has not been one of Pandora's strengths, despite such solid growth and meaningful market share.

Now, with Apple's iTunes Radio, not to mention Google's ( GOOG) All Access service fully in the mix, it just doesn't seem as if Pandora's top-line performance will ever trickle down to profits.

What this means is that,as hard as Pandora has worked to survive the attacks by Sirius, Spotify, iHeartRadio, Last.fm and a host of other Internet rivals, Pandora will now have to double down on its efforts to secure a meaningful chunk of the $4 billion per year U.S. mobile ad market. I believe this should be one of the company's top priorities.

I'm not suggesting Pandora's August numbers are inconsequential. Nor am I saying management doesn't know what it's doing. I just don't believe, however, that the August numbers change any expectations the Street has had on this company. Yes, the metrics were above market expectations. But let's not forget the numbers were coming from a company with negative earnings.

What I mean by this is, while Pandora's growth numbers were indeed impressive, this is precisely the performance for which investors are paying. No one's buying the stock today for the profits. So I wouldn't get carried away.

Also, as has been the case since the company's inception, investors should continue to expect volatility in the shares, especially since we don't yet know how the arrival of Apple and Google is going to disrupt this market.